1-Phenylisatin

In the title compound, C14H9NO2, the phenyl ring makes a dihedral angle of 50.59 (5)° with the mean plane of the isatin fragment. In the crystal, molecules are linked through weak intermolecular C—H⋯O hydrogen bonds. The crystal structure also exhibits two slipped π–π interactions between the benzene rings of neighbouring molecules [centroid–centroid distance = 3.968 (3) Å, interplanar distance = 3.484 (3) Å and slippage = 1.899 (3) Å], and between the phenyl rings of neighbouring molecules [centroid–centroid distance = 3.968 (3) Å, interplanar distance = 3.638 (3) Å and slippage = 1.584 (3) Å].


Comment
Isatin is a commercially available indole derivative. Isatin derivatives are well known for their pharmacological properties such as anticonvulsant activity (Prakash et al., 2010). We report herein the crystal structure of the title compound.
In the title compound ( Fig. 1), the isatin unit is essentially planar, with a mean deviation of 0.004 (2) Å from the least-squares plane defined by the nine constituent atoms. The phenyl ring makes a dihedral angle of 50.59 (5)° with the mean plane of the isatin fragment. The observed C-C bond length of 1.547 (3) Å in diketo moiety is slightly longer than normal C-C bond length (Rathna & Chandrasekhar, 1991). The crystal packing ( Fig. 2) is stabilized by three weak intermolecular C-H···O hydrogen bonds; the first one between a benzene H atom and the O atom of the carbonyl unit (Table   1; C4-H4···O2 i ), the second one between a benzene H atom and the O atom of the carbonyl unit (Table 1; C7-H7···O1 ii ), and the third one between a phenyl H atom and the O atom of the carbonyl unit (Table 1; C11-H11···O2 iii ).
The crystal packing (Fig. 3) is further stabilized by two weak slipped π···π interactions (Fig. 4); the first one between the benzene rings of neighbouring molecules, with a Cg1···Cg1 i distance of 3.968 (3) Å and an interplanar distance of 3.484 (3) Å resulting in a slippage of 1.899 (3) Å (Cg1 is the centroid of the C3-C8 benzene ring), and the second one between the phenyl rings of neighbouring molecules, with a Cg2···Cg2 i distance of 3.968 (3) Å and an interplanar distance of 3.638 (3) Å resulting in a slippage of 1.584 (3) Å (Cg2 is the centroid of the C9-C14 phenyl ring)

Experimental
The title compound, 1-phenylisatin, was purchased from Aldrich Chemical Co.. Single crystals suitable for X-ray diffraction were obtained by sublimation under reduced pressure.

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > 2sigma(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.